Seat With Pivoting Backrest

ABSTRACT

A seat, particularly for aircraft, has a backrest with a high pivot. Such a backrest permits a range of supported semi-reclining seating positions without inconveniencing an occupant of the next rearward seat row. The seat also permits selection of seat pan length to suit the height of the occupant.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority, under 35 U.S.C. §119, of UnitedKingdom Patent Application No. 0809952.5, filed May 30, 2008, whichdesignated the U.S. and was published in English, the entire disclosureof which is hereby incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

This invention relates to a pivoting backrest of a seat, and isparticularly, though not exclusively, intended for use in passengervehicles such as aircraft.

BACKGROUND OF THE INVENTION

Prolonged sitting without substantial change of position is badpractice, and may result in stiffness and pain. Especially in the caseof aircraft, such prolonged sitting has been identified as a cause ofblood clots in the lower leg, which can in turn have serious medicalconsequences. Passengers are encouraged to move limbs, and adoptdifferent positions, but this is rather difficult where seating iscramped, such as in economy class. More generously proportioned seatingleads to an increase in ticket price and may in fact be revisited bythose passengers seeking low cost travel.

U.S. Pat. No. 5,058,954 describes a reclining seat/backrest which in thereclined condition offers little support against the occupant slidingdown the inclined surface. Furthermore the backrest moves rearwardly,and may encroach unacceptably on the occupant of the next rearward seat.In theory, however, this seat configuration allows an occupant tostraighten the legs.

U.S. Pat. No. 5,536,067 describes a chair with a split seat pan, whichmay give better clearance for the upper thighs, yet retain sufficientsupport for the buttocks.

U.S. Pat. No. 5,722,726 discloses a multi-component aircraft seatintended to permit the occupant to adopt a semi-reclined position.

U.S. Pat. No. 6,659,552 proposes an inflatable seat portion whichsupports the lumbar region in an aircraft seat, and allows the occupantto straighten the legs.

U.S. Pat. No. 7,195,316 is a mechanical substitute similar to U.S. Pat.No. 6,659,552, and in which the seat back and seat pan move together toa reclined position without encroaching on the next rearward occupant.In order to allow leg space for the occupant, the seat pan is dividedand the front portion hinges down. Thus this seat has a sloping backrestand short seat pan in the reclined condition, which permits an occupantto straighten the legs.

The latter proposal is mechanically complex, and has numerous movablecomponents and pivots. There is also a risk of broken or damaged parts,for example the split seat pan may be uncomfortable in the normalposition.

What is required is a lightweight and simple seat construction suitablefor close seat pitch, and which permits an occupant to comfortably adoptdifferent postures.

SUMMARY OF THE INVENTION

According to the invention there is provided a seat comprising amounting, a seat pan on the mounting, a frame on the mounting, abackrest pivoted on the frame about a high transverse axis with respectto the seat pan, and a latch to restrain said backrest at a desiredangular position relative to said frame.

In practice many occupants of economy seating tend to adopt a positionin which the buttocks are forward on the seat pan, in order to try andstraighten the legs; sometimes this forward positioning is inadvertent.The present invention allows the back to be supported in such aposition, which is more comfortable for the occupant and has less riskof causing pain.

The mounting is provided for fixing the seat to a substrate, and theframe supports the backrest. The frame may be fixed with respect to themounting, or may be relatively movable—for example as part of a seatreclining mechanism.

In one embodiment the seat pan is fixed; in such a seat, a movingbackrest with a single pivot axis may suffice. The occupant selects adesired rake and latches the backrest to the seat frame. The rake may bechanged on demand, and may provide a range of seat configurations fromfull sitting to semi-reclining.

In another embodiment the seat pan is movable in a generally fore andaft direction for example on a latchable sliding mechanism. In such aconfiguration, the seat pan slides independently of the backrest.

In this configuration, the seat pan length can be selected to give thedegree of buttock support which the occupant desires.

In another configuration a reclining seat is provided with a high pivotbackrest according to the invention. In this configuration, the backrestmaybe moved forward in the reclined position of the seat to give ashorter seat pan length with greater reclining angle.

Preferably, the transverse axis is above mid-height of the backrest, andmost preferably. above three-quarter height. A head rest may be providedon the seat back, or made integral therewith. For the purposes of thisspecification, a seat back terminates at average passenger shoulderheight.

When latched close to the forward end of a seat pan, for example with20% or less of the seat pan exposed, the seat permits semi-reclining ofthe occupant with the buttocks supported on the ledge provided by theexposed seat pan portion. In this position the occupant's back issupported and the occupant's legs are substantially straight, thusavoiding prolonged bending of the body at the pelvis which may give riseto lower back pain.

It will be understood that a seat according to the invention isrelatively inexpensive compared with prior art proposals, and it can bemechanically simple. The high pivot seat allows a close seat pitch, asrequired in economy seating, and does not encroach upon the nextrearwards row.

A further advantage of the invention is that the seat back may beadjusted for normal sitting with several different lengths of seat pan;thus the seat permits comfortable accommodation of both short and tallpassengers.

Although the invention is illustrated and described herein as embodiedin a seat with pivoting backrest, it is, nevertheless, not intended tobe limited to the details shown because various modifications andstructural changes may be made therein without departing from the spiritof the invention and within the scope and range of equivalents of theclaims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof, will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features of the invention will be apparent from the followingdescription of a preferred embodiment shown by way of example in theaccompanying drawings in which:

FIG. 1 is a diagrammatic illustration from the side of a conventionalaircraft seat;

FIG. 2 is a diagrammatic illustration of the seat of FIG. 1 with aperson shown in a typical slumped seating position;

FIG. 3 is a diagrammatic illustration from the side of a seat accordingto the invention in a reclined configuration;

FIG. 4 is a diagrammatic illustration of the seat of FIG. 3 with theseat in a long seat pan configuration;

FIG. 5 is a diagrammatic illustration of the seat of FIG. 3 with theseat in a short seat pan configuration;

FIG. 6 is a diagrammatic illustration of the seat of FIG. 3 with amovable seat pan; and

FIG. 7 is a diagrammatic illustration of the seat of FIG. 3 retrofittedon a reclining seat.

Aspects of the invention are disclosed in the following description andrelated drawings directed to specific embodiments of the invention.Alternate embodiments may be devised without departing from the spiritor the scope of the invention. Additionally, well-known elements ofexemplary embodiments of the invention will not be described in detailor will be omitted so as not to obscure the relevant details of theinvention.

Before the present invention is disclosed and described, it is to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to belimiting. It must be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferences unless the context clearly dictates otherwise.

While the specification concludes with claims defining the features ofthe invention that are regarded as novel, it is believed that theinvention will be better understood from a consideration of thefollowing description in conjunction with the drawing figures, in whichlike reference numerals are carried forward. The figures of the drawingsare not drawn to scale.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a conventional aircraft seat 10 comprises aseat pan 11 and a backrest 12. Not shown in FIG. 1 is the usual seatframe, leg(s), armrests and headrest. The seat frame supports the seatpan and backrest; typically in an economy seat, the seat pan is fixed,and the backrest is pivoted at the lower end to allow a limited amountof reclining (as shown in dotted outline 13).

As illustrated in FIG. 1, the backrest provides support for theoccupant's back, and the seat pan provides support for the thighs.Necessarily, the length of seat pan (fore and aft) is a compromise andmay not be comfortable for very short or very tall occupants.

FIG. 2 illustrates in somewhat exaggerated form a common posture adoptedby an occupant during a long haul flight in an economy seat. The buttockregion moves toward the front end of the seat pan in order that theoccupant can straighten the legs 14, but as a consequence much of theoccupant's back and spine region 15 is unsupported and thus may resultin lower back pain.

The invention is illustrated in FIG. 3. A backrest 22 is pivoted on aseat frame at the high end; as illustrated a pivot axis 24 is at thevery top of the backrest 22, but it need not be. The seat pan 21 can beattached to the seat frame, and may be movable as further describedbelow.

For take-off and landing, and if desired by the occupant, the backrestis fixed in a conventional upright position, as illustrated in dottedoutline 24.

However, when permitted, the occupant may pull the lower end of thebackrest 22 forward so as to permit full straightening of the legs 14whilst ensuring that the back and spine region 15 is fully supported.The occupant's buttocks are supported by a short protruding portion ofthe seat pan 21, typically 25% or less of the overall fore and aftlength.

Any suitable measures for latching the backrest 22 can be used, forexample spring loaded plungers on either side of the backrest 22 mayengage in non-illustrated rails having plunger receiving apertures atsuitable spacings. The occupant merely moves to the front of the seatpan 21, and eases the backrest 22 forward. A motorized motion isrelatively simple to configure because a single moving seat part isprovided—for example a screw jack in either armrest may be sufficient.

FIGS. 4 and 5 illustrate how the adjustable backrest allows acomfortable length of seat pan 26 for both tall (FIG. 4) and short (FIG.5) occupants.

FIG. 6 illustrates a movable seat pan variant in which a seat pan 31 isslidable fore and aft. The seat pan 31 is moved by the occupant, and islatchable at a desired fore and aft position. A backrest 34 isindependently latchable so as to give a range of seating positions. Thisconfiguration allows a sloping backrest with a full length seat pan, atthe expenses of reduced leg room.

FIGS. 7 a to 7 d illustrate the affect of the invention applied to areclining seat of the kind usually provided for business classtravelers.

FIG. 7 a shows a reclining seat 41 in the upright condition, and FIG. 7b illustrates a high pivot backrest 42 in rear and forward conditions.

FIG. 7 c shows the seat 41 in the reclined condition, and FIG. 7 d showsthe affect of pivoting the high pivot backrest 42 to give a shorter seatpan 43 with additional reclining of the backrest 42. It will beunderstood that, in this embodiment, the reclining mechanism of the seat41 incorporates the pivot frame of the backrest.

As is clear from the drawings, variation of backrest angle does notsubstantially reduce the space available for the next rearwardpassenger.

Although the invention has been described in relation to aircraft seats,it will be understood that it is applicable to transportation seatinggenerally, and may also be suitable for buses, trains and the like.

The foregoing description and accompanying drawings illustrate theprinciples, preferred embodiments and modes of operation of theinvention. More specifically, the seat with pivoting backrest accordingto the present invention has been described. However, the inventionshould not be construed as being limited to the particular embodimentsdiscussed above. Additional variations of the embodiments discussedabove will be appreciated by those skilled in the art as well as forapplications, unrelated to inventory, that require encryptedidentification of parts.

The above-described embodiments should be regarded as illustrativerather than restrictive. Accordingly, it should be appreciated thatvariations to those embodiments can be made by those skilled in the artwithout departing from the scope of the invention as defined by thefollowing claims.

1. A seat comprising a mounting, a seat pan on the mounting, a frame onthe mounting, a backrest pivoted on the frame about a high transverseaxis with respect to the seat pan, and a latch to restrain said backrestat a desired angular position relative to said frame.
 2. The seataccording to claim 1 wherein said frame is reclinable with respect tosaid mounting, and is latchable at a desired reclining angle.
 3. Theseat according to claim 1 wherein said backrest has a mid height andsaid axis is above the mid height of said backrest.
 4. The seataccording to claim 3 wherein said backrest has a three-quarter heightsaid axis is above three-quarter height of said backrest.
 5. The seataccording to claim 4 wherein said axis is above 90% of a height of saidbackrest.
 6. The seat according to claim 1 wherein said seat pan isfixed with respect to the said frame.
 7. The seat according to claim 1wherein said seat pan is fixed with respect to said mounting.
 8. Theseat according to claim 1 wherein said seat pan is movable fore and aftindependently from the backrest and has a plurality of latchablepositions with respect to said frame.
 9. The seat according to claim 8wherein said seat pan is slidable.
 10. The seat according to claim 1wherein, in a forward most position of said backrest, said backrestexposes 50% or less of a length of the seat pan.
 11. The seat accordingto claim 9, wherein 25% or less of a length of said seat pan is exposed.12. The seat according to claim 1 wherein, in a rearward most positionof the backrest, the backrest exposed substantially the entire seat pan.13. (canceled)
 14. A seat retrofit device, comprising: a seat-fixationmounting (black bottom) capable of attachment to a substrate, saidmounting having a fore end and an aft end to define a fore-to-aftextent; a lower seat pan (43) disposed at said mounting and extending ina plane from approximately said fore end to approximately said aft end;a frame (black back) disposed at said aft end of said mounting at anangle with respect to said lower seat pan and having a frame upper end;an upper backrest (42) pivotally connected at said frame upper end aboutan axis transverse with respect to the fore-to-aft extent; and a latchcapable of restraining said backrest at a pre-defined set of angularpositions relative to said frame.
 15. The seat according to claim 14,wherein said frame is capable of being reclined with respect to saidmounting and being removably secured in at least one pre-definedreclining angle.
 16. The seat according to claim 1, wherein said axis islocated at a top half of said backrest.
 17. The seat according to claim1, wherein said axis is located at a top quarter of said backrest. 18.The seat according to claim 1, wherein said axis is located at a toptenth of said backrest.
 19. The seat according to claim 1, wherein saidseat pan is fixed with respect to at least one of said frame and saidmounting.
 20. The seat according to claim 1, wherein said seat pan ismovable in said fore-and-aft extent independent from said backrest andhas a plurality of latchable positions with respect to said frame. 21.The seat according to claim 20, wherein in a fore-most position saidbackrest exposes no greater than 50% of a length of said seat pan. 22.The seat according to claim 21, wherein in a fore-most position saidbackrest exposes no greater than 25% of a length of said seat pan.
 23. Aseat according to any preceding claim wherein in the rearward mostposition the backrest exposed substantially the entire seat pan.